The Real-Time Displayal of the Hardy Weinberg Theory Niah 1

Simulating Hardy-Weinberg’s Theory

Arizo Niah

February 15, 2020

Lab Report 1

BIOL-1405-005
The Real-Time Displayal of Hardy-Weinberg Theory Niah 2

Introduction

Hardy Weinberg’s theory is an important concept of biology. The theory basically states that

there will be equilibrium among the gene flow of a species if certain factors are met. In simpler

words, a species will not change or evolve, if five specific criteria are met. Those five criteria are

as follows; There must not be any mutations, the population must be large, mating should be

random, no natural selection must be occurring, and no migration of the species should be taking

place. If a population meets all of that criteria, then no change will occur within that species trait

frequencies. For example, if a population has 50% black cats, 10% tuxedo cats, annd 40% white

cats, then that population would remain that way, close to the same percentages, until the

equilibrium is disturbed by the breaking of one of the five criteria. For example, if the white cats

were suddenly targeted due to their fur color, their population would both dwindle and go

through natural selection, which is against the Hardy-Weinberg equilibrium. If the white cats

were hunted down to low numbers, then that would make black and tuxedo cats more common,

possibly also wiping out the white cat population and making them much rarer. That is change.

When there is Hardy-Weinberg equilibrium however, there is no change.

Along with this theory of Hardy-Weinberg equilibrium, is an equation that goes along

with it. When a population is in equilibrium, its numbers can be represented by two sets of

equations. The equation p+q=1.0 represents the phenotype (characteristic) of the species, with p

2 2
being the dominant allele or trait and q being the recessive. Then the equation 𝑝 + 2𝑝𝑞 + 𝑞

2
represents the whole genotypes of the populations. The 𝑝 is the homozygous dominant trait, the

2
2𝑝𝑞is the heterozygous trait, and then lastly, the 𝑞 is the homozygous recessive trait. Using this

equation, people can use this to estimate and figure out data based on population numbers of

species who are in equilibrium. Using this equation, people can also figure out if a population is

going through any disruptencies, such as migration or natural selection.

Methods

To test out the Hardy-Weinberg theory, students each had their own allele type and

randomly selected mates to reproduce with. Their offspring were also randomly selected each

time depending on their parents alleles. Their first experiment consisted of no disruptencies,

complete Hardy-Weinberg equilibrium. Only the random mating of 36 individuals. The allele

frequencies that were started with are in the table in figure 1, located in the results. The

hypothesis before the experiment began was that all frequencies would be close to the same as

they started with. After each individual mated 7 times, the data received is in figure 2, also

located in the results.

In the second experiment, the mating was switched up a bit. The ones with homozygous

recessive genes dyed off and were eliminated from the gene pool, leaving only the homozygous
The Real-Time Displayal of Hardy-Weinberg Theory Niah 4

dominant people and heterozygous to procreate. It was hypothesized that the number of recessive

alleles would stay very low because of the selection taking place in getting rid of the

homozygous recessive people. The number of individuals and their genotypes can be found in

figure 3. After the experiment, it was found that the homozygous recessive individuals were able

to spring back up, regardless of the fact that their prior ancestors dying off. The seventh

generation of offsprings can be found in figure 3 as well.

Results

Fig 1.

INDIVIDUAL GENOTYPES IN OUR POPULATION FOR EXPERIMENT 1

AA: 5 individuals Frequency: 28% ALLELE FREQUENCY

Aa: 9 individuals Frequency: 50% A: 58%

Aa: 4 individuals Frequency: 22% A: 47%

Fig 2.

Number of Individuals (Total:256) After Experiment 1.

AA: 59 Aa: 139 Aa: 54

AA: .288 (28.8%) Aa: .497 (49.7%) Aa: .214 (21.4%)

A: 78.6% ----------------------------------- a: 21.4%

Fig 3.

First Generation of individuals in Experiment 2

AA: 8 Aa: 28 Aa: 0

AA: 8 Aa: 28 Aa: 6

Discussion

In experiment 1, nothing was changed in the species population. Equilibrium was

undisturbed and mating was random. All five criteria were met in Hardy-Weinberg’s theory. As a

result, it was hypothesized that the frequencies would stay relatively the same throughout the

generations and breeding processes. The data collected in the end does support the hypothesis.

The percentages were very close. For example the homozygous dominant allele in the beginning

was 28% in frequency, and after 7 matings, it remained in the 28% range (28.8% exactly). The

numbers highlighted in blue are comparisons to the first generation versus the generation after 7

matings. No evolution took place since the alleles were consistent in frequency and no change

happened in the gene pool.

In experiment 2, the population started with a disaster, killing off every homozygous

recessive individual there was. As a result, the first generation started off with only heterozygous

and homozygous dominant individuals. This disrupted Hardy-Weinburg’s theory of equilibrium

because natural selection occured. Because of this, Hardy-Weinburg’s equation may not be used
The Real-Time Displayal of Hardy-Weinberg Theory Niah 6

either because the amount of homozygous recessive individuals is nonexistent in the first

generation. However, as the generations of mating began, by the time 7 matings had been done,

it had seemed that the homozygous recessive gene sprang up again. The generation started with

no homozygous recessive individuals, but ended with 6 (as shown in figure 3). Because of this

drastic change from generation 1 to generation 7, it can be concluded that change has occurred,

concluding that evolution has taken place. This also shows that equilibrium may be gradually

restored if the five criteria are met again, even after a disaster that wipes away a certain

genotype. In this case, the equilibrium was revived by the random mating again. This would not

have happened, however, if the homozygous recessive allele resulted in fatality. If that were the

case, homozygous recessive individuals would be nonexistent because they would all end up

dying. They may still be born, if two heterozygous individuals procreate, but they will never

fully survive. The results received did match up with the hypothesis; That eventually the

homozygous recessive gene would come back again, but it’s numbers would start off low.

However, It had not been concluded in the hypothesis that equilibrium would be restored,

making the hypothesis weak and partially faulty for the second experiment.